DURHAM — Dr. Janet Perkins Howland has run the Boston Marathon so many times, she has lost count.

On Monday, the Durham resident had just crossed the finish line at the 117th running of the world-famous race when she heard the first of two blasts.

“I looked back and saw the plume of smoke and less than 10 seconds later another one went off,” Perkins-Howland said. “People panicked, and even though they had just finished running, they had found a new energy. The only people running toward the explosion were people with TV cameras. The poor volunteers didn’t know what to do.”

Well after the top runners had finished on Monday, a pair of bombs exploded near the finish line. Two people were killed and at least a 100 were injured.

Perkins Howland finished Monday’s race in four hours, four minutes and one second, one day shy of her 51st birthday.

“I kind of bent down to catch my breath and heard an enormous crash-bang,” she said. “All your senses are hyper after running a marathon, so it was very confusing because you’re just so fatigued.”

Fortunately for Perkins Howland, none of her family members were near the scene of the bombing. Dr. Howland’s husband, Al Howland, normally stands near the finish line to cheer on his wife, but on Monday made a last-minute decision to meet Dr. Howland at a different location.

“I was getting the car,” Howland said. “Normally my wife’s brother and I go to watch her at the finish line. This year I just decided to park by the (TD Garden). We saw her at Mile 22 and I figured I’d meet them at the finish line. I don’t know if I would have been at the finish line at the same time (of the explosion) but I was glad I had the change of plans.”

Durham’s Vicky Miller was still racing just yards from the finish line when she heard the first bomb go off.

“Debris sprayed across the pavement in a fireball, and I just laid down,” Miller said. “I knew it was a bomb and I was mad right off the bat. I was worried about the people because I could tell it was on the side of the spectators.”

Miller was in charge of a bus carrying more than 50 members of her running club, 45 of whom were running the marathon. Miller spent most of the night tracking down the runners, some of whom were unable to finish the race because of the incident. She said by the end of the night all of the club members were accounted for.

“I got through the finish line and I couldn’t see any of the other runners behind me,” said Miller, 60. “I got through there and I could hear people yelling ‘Clear the road.’”

Dr. Perkins Howland said since she was aware of her husband’s decision not to meet up at the finish line, she wasn’t worried about him at the time of the blast. She was just trying to find her personal belongings and a way to safely meet up with her husband.

“I was just trying to follow directions,” Perkins Howland said. “I got all the way back to our hotel, and that had turned out to be evacuated. Then I went into a restaurant and they had to evacuate that, too. But we found each other at the Boston Common.”

Perkins Howland eventually retrieved her race bag, which contained her cell phone. Retrieving his car a few miles from the unfolding chaos, Al Howland was at first unaware that anything unusual had happened.

“I came out at Government Center and there were all these sirens going off,” Howland said. “I couldn’t get ahold of her on her cell phone. I heard that some spectators were badly injured. I knew that was the time she usually finished.”

Al Howland said since cell phone lines were jammed, he resorted to using a pay phone to reach his wife.

“It’s fortuitous that he changed plans,” Dr. Perkins Howland said.

Eventually, the pair met up, and immediately decided to drive back to Durham, leaving their personal belongings at the hotel.